"If you stand here under I-495, this isn't just a Delaware issue. It's a national issue," Foxx said. "When this bridge goes down, the ability of folks to travel all the way south into Miami, all the way up the Eastern Seaboard is impacted. So it is a big deal that we get this bridge back up and running."

Delaware's massive expense is believed to have resulted from avoidable damage caused by a huge and misplaced mass of soil. But Foxx said the disruption illustrates the potential problems ahead if the nation's Highway Trust Fund runs short of cash this summer.

Without a congressional fix, Foxx said, a Highway Trust Fund meltdown would mean that "states all across this country are either going to slow down or even stop projects from moving forward -- critical projects that support our country, our quality of life, the efficient flow of goods and the efficient flow of people."

Engineers believe that soil stockpiling on land adjacent to the bridge right-of-way squashed surrounding soft soils, with damaging compression extending to deeply driven piles and concrete bridge substructures nearby, where it caused dangerous bending and cracking. By last week, travel lanes had tilted noticeably, with the passing lane retaining wall of the northbound span swinging up as much as 18 inches.

The Federal Highway Administration approved $2 million in immediate emergency aid for an investigation and repairs to the span's southern approaches, which carried about 90,000 vehicles a day.

Usually-heavy summer Friday traffic was snarled in all directions by mid-afternoon, with long backups on I-95 and congestion on major arteries through and around Wilmington and clogged streets around the port complex.

DelDOT earlier this week announced a $20 million temporary repair plan that could reopen southbound lanes as early as Labor Day.